Add gitea at git.rubenhensen.nl

Single-pod sqlite install (simplest path for a home git host). HTTPS-only,
no SSH listener for now. Wired into the Hetzner tunnel like the other
rubenhensen.nl services.

First visitor to git.rubenhensen.nl can register; Gitea auto-promotes the
first user to admin.

gitea/gitea-data-persistentvolumeclaim.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: gitea-data
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 10Gi